Uranium stability in a large wetland soil core probed by electron acceptors, carbonate amendments and wet-dry cycling in a long-term lysimeter experiment.
Sci Total Environ
; 803: 149783, 2022 Jan 10.
Article
em En
| MEDLINE
| ID: mdl-34482132
ABSTRACT
Understanding the hydro-biogeochemical conditions that impact the mobility of uranium (U) in natural or artificial wetlands is essential for the management of contaminated environments. Field-based research indicates that high organic matter content and saturation of the soil from the water table create favorable conditions for U accumulation. Despite the installation of artificial wetlands for U remediation, the processes that can release U from wetland soils to underlying aquifers are poorly understood. Here we used a large soil core from a montane wetland in a 6 year lysimeter experiment to study the stability of U accumulated to levels of up to 6000 ppm. Amendments with electron acceptors showed that the wetland soil can reduce sulfate and Fe(III) in large amounts without significant release of U into the soil pore water. However, amendment with carbonate (5 mM, pH 7.5) resulted in a large discharge of U. After a six-month period of imposed drought, the re-flooding of the core led to the release of negligible amounts of U into the pore water. This long-term experiment demonstrates that U is strongly bound to organic matter and that its stability is only challenged by carbonate complexation.
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1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Urânio
Idioma:
En
Ano de publicação:
2022
Tipo de documento:
Article